FMRF-amide-related peptides (FaRPs) are small peptides of 4–18 amino acids with RFamide (arg-phe-NH2) at the C terminus. The first RFamide peptide was isolated in 1977 by Price and Greenberg as a cardioexcitatory peptide from the cerebral ganglia of Venus mussel; since then, other FaRPs have been described in the nervous systems of all major animal phyla, including vertebrates. Aside from the known function of regulating feeding, FMRF amide related peptides have been found to stimulate growth hormone release in amphibians; modulate central serotonergic transmission, the opioid systems and pain regulation in vertebrates; and produce antipsychotic-like effects when centrally administered in rodents.